For a perfectly black body,the coefficient of emission (emissivity) is:

There is a black spot on a body. If the body is heated and carried into a dark room,then it glows more than the rest of the body. This can be explained on the basis of:

The Sun emits radiation in all directions. The Earth receives approximately $1.4 \ kW/m^2$ of radiation per second. The distance between the Sun and the Earth is $1.5 \times 10^{11} \ m$. How much mass does the Sun lose per day? $(1 \ \text{day} = 86400 \ s)$

For a perfect black body,the absorption coefficient is

If $150 \,J$ of energy is incident on an area of $2 \,m^{2}$. If $Q_{r}=15 \,J$ and the coefficient of absorption is $0.6$,then the amount of energy transmitted is: (in $\,J$)

At a high temperature,a body emits radiation of wavelengths $\lambda_1, \lambda_2, \lambda_3,$ and $\lambda_4$ only. At a lower temperature,which of the following wavelengths will it absorb?